Energy-conservation and utilization of solar energy are new trends of the development of the world. Currently, various related technologies and products are increasing, but the cost and the efficiency have been bottlenecks of energy-conservation and utilization of solar energy. There exist the following particular problems:
Firstly, the solar water heater has been widely used, but its cost is very high. What's more, the higher the efficiency is, the higher the cost. Additionally, either the heater is set on the roof or on the balcony, it will deface the general appearance of the buildings.
Secondly, the cost of solar power photovoltaic generation is extremely high, but its efficiency is too low.
Thirdly, the cost of buildings-insulation is high, but the heat is simply insulated without utilization.
Finally, recovery and utilization of rainwater is rarely applied to buildings, except to some conceptual architecture, for the reason that considerable capital needs to be invested to build a set of system, although the cost of the system is not high, its cost performance is too low relative to its function.